Question about regaining RAM

[signal34]

I have an icon on my Today screen which shows me the amount of RAM that's available for use. Whenever I soft reset, the value starts at around 55%. Whenever I open a program, the percentage drops, as it should, since the program is using RAM.

My problem is that after some hours of use (opening a program here, closing a program there), when I close all open programs, my percentage stays around 20%. I've used Reclaim RAM to try to recapture it, but it always gives me a message that there is none to be reclaimed.

I check my running apps using Memmaid and see that there's nothing out of the ordinary that shouldn't be running.

My questions are:
1. Are there programs I'm possibly using that just don't dump the RAM back to the system like they should after they're closed?

2. Does anyone know of programs other than Reclaim RAM that will actually get back unused RAM?

3. Does anyone know of a list of programs that may be culprits in not dumping RAM back to the system like they should when closed?

Thanks for any and all responses.